New insights into the past and recent evolutionary history of the Corsican mouflon (Ovis gmelini musimon) to inform its conservation

Abstract

Human-mediated species dispersal across the Mediterranean stretches back at least 10,000 years and has left an indelible stamp on present-day biodiversity. Believed to be a descendant of the Asiatic mouflon (Ovis gmelini gmelinii), the Corsican mouflon (O. g. musimon) was translocated during the Neolithic as ancestral livestock by humans migrating from the Fertile Crescent to the Western Mediterranean. Today, two geographically limited and disconnected populations can be found in Corsica. Whether they originated from distinct founders or one ancestral population that later split remains unknown, although such information is pivotal for the species’ management on the island. We genotyped 109 and 176 individuals at the Cytochrome-b gene and 16 loci of the microsatellite DNA, respectively, to gain insights into the natural history of the Corsican mouflon. We found evidence confirming that the Asiatic was the ancestor of the Corsican mouflon, which should thus be unvaryingly referred to as O. g. musimon, i.e. as a subspecies of the Asiatic mouflon. Haplotype divergence dating and the investigation of genetic structure highlighted a strong and ancient genetic differentiation between the two Corsican populations. Approximate Bayesian Computation pointed to the introduction of a single group of founders as the most reliable scenario for the origin of the entire Corsican population. Later, this ancestral stock would have decreased in number, facing genetic bottlenecks and eventually resulting in two divergent demes. Splitting most likely occurred several hundred years ago. Their shared past notwithstanding, we discuss whether the two relic Corsican mouflon populations should be now considered as distinct management units.